It's a wonderful book of interviews with 27 leading cosmologists where they discuss many subjects: their youth and how they became cosmologists, their (possibly changing) views on the correct model for the universe, and their philosophical perspective on whether the universe has any "point." In addition, there is a wealth of references, which include papers and books written by the interviewees, along with seminal papers in the history of cosmology.
Jim Peebles is, of course, one of the 27. Unfortunately, people like Edwin Hubble and Milton Humason had died by 1990 and were not included. I thought I'd give a brief overview of each cosmologist and their insights.
The first on the list is Fred Hoyle (1915-2001), one of the older interviewees. He first discusses his sophistication at age 12 (!):
By the time I was around 12, I had understood the difference between being a layman who is interested and having a real understanding. Out of this grew my strong feeling that before one can be involved in science, one has to have a tremendous sense of craftsmanship. I still get mountains of letters from the lay public, proposing various ideas, and you can chuck it all out because you know that the brain isn't properly ordered to understand the problems they aim to solve.It is true that those without a scientific background tend to underestimate the knowledge and understanding needed to do science, especially physics. They have a neat idea, and they often feel that that's all it takes to overthrow decades of work by professionals. Unfortunately, they often don't have the background to know that what they're doing is wrong. It's quite amazing that Hoyle felt that he was able to distinguish crackpots from such a young age.
Hoyle is one of the more famous (perhaps the most famous) proponent of the steady state theory of the universe. This is the idea that even though it appears that the universe is expanding, it really is in some kind of "dynamic steady state," and that it would look the same as viewed at any epoch. And his recollection of how that model came about is interesting. First there was the article "Relativistic Cosmology," by H.P. Robertson in 1933 in Reviews of Modern Physics. He and Hermann Bondi were wondering if Robertson had really considered all the possibilities, all the possible models for the universe. Thomas Gold suggested that the universe might be steady state, which was something that Robertson had not considered in his article. Then Bondi and Hoyle said that model would require the creation of matter, and they didn't like that aspect. After a while, Hoyle found a physical model that could account for the matter creation - "a crude way of coupling a scalar field to gravity" - and all three gradually came around.
Quite apart from championing the idea of the steady state universe, Hoyle says that "I didn't go beyond saying that the steady state theory is a possibility. When I have defended it, I always defended it on the grounds that what were claimed as disproofs were things that a mathematician would not regard as disproofs. They were full of holes."
It appears that now, after much new observational data, there are few (or none) cosmologists who still defend the steady state theory. Along with Hoyle, Bondi and Gold are dead. Jayant Narlikar, who developed with Hoyle a theory of gravity specifically to mesh with the steady state model, is 81 years old, but I have not read any recent strong statements from him. The Hoyle-Narlikar theory of gravity is incompatible with the expanding universe and doesn't fit the recent observational data, so that is probably a dead end, too.
In the physics community, however, Hoyle is also famous for predicting the 7.6 MeV excited state of the carbon-12 nucleus that was necessary for models of nuclear fusion in stars to produce the necessary quantities of heavy elements (see here). But that is another story ...
